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links not shown in van sdn controller

pman1
Visitor

links not shown in van sdn controller

Hello,

I use HP Network Simulator with gns3. I did a simple topology with 2 switches in HNS, and I put them in gns3 with 2 hosts.

Here is my configuration in HP Network Simulator:http://hpics.li/6b8e051

Here is the topology in gns3: http://hpics.li/c896895

Here is the config of the switch connected to the outside (the hp sdn controller) via the cloud: http://hpics.li/2007285 and http://hpics.li/7c47b82

My problem is that the switches are not linked in the controller : http://hpics.li/8686bf2

I can't see the hosts either, when I ping from host 1 to host 2. Pings are working between hosts and the packets are correctly sended throughout the switches.

Thanks for your help.

5 REPLIES
ShaunWackerly
Trusted Contributor

Re: links not shown in van sdn controller

Hi pman1,

Could you please show a few items from the VAN SDN controller? Specifically I'd like to see:

  • the list of flows on each switch (OpenFlow Monitor -> Flows)
  • the controller configuration (Configurations -> Basic -> com.hp.sdn.ctl.of.impl.ControllerManager)
  • the link discovery configuration (Configurations -> Advanced -> com.hp.sdn.disco.of.link.impl.OpenflowLinkDiscoveryComponent)

I think the behavior you're seeing is caused by the BDDP/LLDP discovery packets either not being sent or not being stolen/received, but it will take more information to find root cause.

In addition, you may want to check the following link discovery guide to ensure your configuration matches what's recommended:

https://community.arubanetworks.com/aruba/attachments/aruba/SDN/45/1/HPN%20SDN%20Controller%20Link%20Discovery.pdf

Shaun

pman1
Visitor

Re: links not shown in van sdn controller

Thanks a lot for your answer.

Here is :

the list of flows on each switch  : http://hpics.li/6a07217 and http://hpics.li/94ad6c0

the controller configuration : http://hpics.li/7636f31

the link discovery configuration : http://hpics.li/2531c98

I think that the configuration matches what is recommended, but I'm not sure.

ShaunWackerly
Trusted Contributor

Re: links not shown in van sdn controller

Hi pman1,

From what I can tell, the data you've shown below looks correct. With the controller configuration shown, each switch should be instructed to generate a multicast BDDP packet every 10 seconds for each port. The BDDP packet should be redirected to the controller (via the default flows shown) where the controller will use the received BDDP packet to discover the link. This isn't happening, so we'll need to dig in deeper.

Would you be able to tear down the environment, start the following packet capture on the VAN SDN controller, and then initialize the simulated network while the packet capture is running? This would capture the complete control-plane conversation between the switches and controller.

tcpdump -i eth0 -w controlplane.pcap

(The above command assumes 'eth0' is the control-plane interface for your VAN SDN controller)

Also if you could attach your VAN SDN controller logs after the packet capture, that would be very helpful to identify what is happening on the VAN side. This packet capture will at least let us know whether the controller isn't generating the packets, or isn't receiving them, or isn't responding to them. I appreciate your continued patience.

Shaun

pman1
Visitor

Re: links not shown in van sdn controller

Hi Shawn,

I tried what you told me with tcpdump, but it doesn't give much result. I didn't know what the control-plane interface of my controller was, so I tried with loopback and eth1.

Here is tcpdump with eth1: https://ufile.io/n5et9

with loopback: https://ufile.io/vnflk

Here is a little schema for understanding: http://hpics.li/ce84b70

I've got two virtual machines that communicate with eth1. I use port forwarding to connect to localhost:8443.

I tried with mininet because it's maybe the same problem with my hp switches, it can maybe help.

If I use mininet on vm0 (controller), switches and hosts can ping. Links are shown on the controller.

But it's not working on vm1. They can't ping except if I put them on the same network as localhost (127.0.0.1). Links are not shown on the controller either way. Maybe I have to forward to 10.252.0.3 instead of localhost in my config?

As for the logs of mininet in the controller, there is one line that changes between what works and what not:

http://hpics.li/649fbd4

Here is the log of the switches on the controller: http://hpics.li/4cd7fed

I don't know how to configure snmp on the controller, I only configured snmp for Intelligent Management Center (if it can help, on IMC, links are shown between hp switches in the normal topology, but not on the openflow topology in the sdn module).

Sorry for my very long message, and thanks for the great help.

Pierre

 

 

ShaunWackerly
Trusted Contributor

Re: links not shown in van sdn controller

Hi Pierre,

I forgot to mention that the 'tcpdump' command I posted will log all of the captured packets into a file named controlplane.pcap. Therefore, on-screen you're seeing the summary (how many packets were captured) but the actual data is contained in the controlplane.pcap file. I think we'd need you to upload that file as an attachment, because posting a screenshot of it wouldn't give the whole picture. You can attach the file if you compress it as a .zip file, I believe.

SNMP key management in the controller is performed via the REST API. You can read about it under the "Managing SNMP keys" section of the VAN SDN Controller Administrator Guide. In the 2.7 version, this is on pages 179-180.

Shaun